> For the complete documentation index, see [llms.txt](https://docs.crosscurve.fi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.crosscurve.fi/developer-documentation/integration-guide-old/direct-integration-with-rest-api.md).

# Direct Integration with REST API

CrossCurve MetaLayer API enables cross-chain token swaps across various networks.

### Base URL

CrossCurve MetaLayer API is built on REST principles and is served over HTTPS.

```
https://api.crosscurve.fi
```

### Authentication

Protected endpoints (`/routing/*`, `/pimlico/*`, `/networks`) require an `api-key` header.

```
api-key: YOUR_API_KEY
```

### Rate Limits

| Tier     | Limit      |
| -------- | ---------- |
| standard | 60 req/min |
| free     | 20 req/min |

### EOA Swap

A standard wallet swap (MetaMask, WalletConnect, or any EOA signer) in six steps:

1. Fetch supported networks and tokens
2. Find a route
3. Approve token spending (ERC-20 only)
4. Send swap transaction
5. Extract requestId from receipt
6. Poll for completion


---

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